I like how, in this moment, they both acknowledge that there were always problems, but COVID revealed them. Later, R will claim that she never knew of any problems.
I also get the vibe that R doesn't want Janelle to remain in the marriage, and that Janelle knew this and trolled her for a minute. I don't think R wanted monogamy. She just wanted it to be her, Christine, and Meri since K didn't have strong feelings for them anymore. Janelle was still competition.